<%@page contentType="image/jpeg" import="java.awt.*, java.awt.image.*,java.util.*,javax.imageio.*" %>
<%!
// 该逻辑可独立运行
// http://a455360448201209214217.iteye.com/blog/1953785
public Color getRandColor(int fc,int bc){
	Random random = new Random();

	if(fc>255) fc=255;
	if(bc>255) bc=255;

	int r=fc+random.nextInt(bc-fc);
	int g=fc+random.nextInt(bc-fc);
	int b=fc+random.nextInt(bc-fc);

	return new Color(r,g,b);
}
%>
<%
	out.clear();//这句针对resin服务器，如果是tomacat可以不要这句
	response.setHeader("Pragma","No-cache");
	response.setHeader("Cache-Control","no-cache");
	response.setDateHeader("Expires", 0);

	int width=60, height=20;
	BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
	Graphics g = image.getGraphics();
	Random random = new Random();

	g.setColor(getRandColor(200,250));
	g.fillRect(0, 0, width, height);
	g.setFont(new Font("Times New Roman",Font.PLAIN,18));
	g.setColor(getRandColor(160,200));

	for (int i=0;i<155;i++){
		int x = random.nextInt(width);
		int y = random.nextInt(height);
		int xl = random.nextInt(12);
		int yl = random.nextInt(12);
		g.drawLine(x,y,x+xl,y+yl);
	}
	String sRand="";
	for (int i=0;i<4;i++){
		String rand = String.valueOf(random.nextInt(10));
		sRand += rand;
		g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt(110)));
		g.drawString(rand,13*i+6,16);
	}

	// 将认证码存入SESSION
	session.setAttribute("rand",sRand);
	g.dispose();
	ImageIO.write(image, "JPEG", response.getOutputStream());
%>